docs: def add_portals_from(self, seq, symmetrical=False):
          """Take a sequence of (origin, destination) pairs and make a
          :class:`Portal` for each.
  
          Actually, triples are acceptable too, in which case the third
          item is a dictionary of stats for the new :class:`Portal`.
  
          If optional argument ``symmetrical`` is set to ``True``, all
          the :class:`Portal` instances will have a mirror portal going
          in the opposite direction, which will always have the same
          stats.
  
          """
          for tup in seq:
              orig = tup[0]
              dest = tup[1]
              kwargs = tup[2] if len(tup) > 2 else {}
              if symmetrical:
                  kwargs['symmetrical'] = True
              self.add_portal(orig, dest, **kwargs)